The bicycle is an engineering marvel – highly efficient at harnessing the energy that you kick out. As anyone who has cycled far and then pondered the long, daunting journey back knows, however, cycling is tougher than it looks – no matter how many gears you have to play with – shift down and you just go slower. In snappy succession, here are the world’s most demanding bicycle races – extreme tough-terrain events that require tremendous endurance and then some. These are the hardest bike rides.

Tour de France

The subject of a classic electropop Kraftwerk song, Tour de France is the most famous and glamorous cycling race in the world by a mile. The Tour de France is also immensely difficult. This year, after the “prologue,” a rider has to cover no less than 3,479 kilometres – farther than the distance between Perth and Sydney. That’s pretty far. During the race, you spend six days in the Alps and 11 in the Pyrenees.

“Tour de France is arguably the most physiologically demanding of athletic events,” the New York Times has said.

The Times likened the effort to “running a marathon several days a week for nearly three weeks.” The Tour de France is widely seen as one of the greatest races of any kind, up there with the Dakar off-road rally. The latest and 99th Tour de France runs from Saturday June 30 to Sunday July 22.

Adding to the intrigue, each year the route changes. But the finish – usually a freewheeling affair because the winner has already been decided – is always in Paris.

Race Across America

If you think the Tour de France is hard, then imagine how steely you must be to finish the Race Across America. The Race Across America is 30-percent longer than the Tour de France and, unlike its Gallic counterpart, non-stop. There’s no hopping off to admire the view here. Worse, you are scarcely allowed any sleep. The amazing ordeal kicks off at Oceanside Pier, California. You squeeze the brakes for the last time in Annapolis, Maryland. The route covers 3,000 miles and involves 170,000 feet of climbing. En route, you cross 12 states, and zing through 88 counties. Hard enough for you?

Just to rub it in, you must complete the distance in half the time allowed for the Tour. No wonder only half of all entrants finish. In fact, only 200 racers have ever crossed the Race Across America finish line. More extreme sports enthusiasts summit Everest than finish the race said to be the holy grail of “ultracycling.” Contestants have died, been injured and even gone crazy. Hell on wheels is an understatement for this bike ride. Only the mega-fit and ice-cool come through.

La Ruta Conquistadores

Is Tour de France and Race Across America to mellow for you? Well then, consider the rugged charms of La Ruta Conquistadores. Pitched as “more than a race – a personal growth journey,” La Ruta isn’t for the faint of heart.

La Ruta Conquistadores may well be the world’s toughest mountain bike race. Held yearly, the race crosses Costa Rica from the Pacific coast to the beaches of its Caribbean shore, taking you through the country’s central highlands in a four-day, extreme endurance trial, or, personal growth journey.

The race has a cool background. Over 20 years back, entrepreneur Roman Urbina decided to shadow the footsteps of Spanish Conquerors Juan de Cavallon and Perefan de Ribera by leading a bunch of mountain bike riders along the trail the conquerors took in 1560. This ride evolved into the La Ruta De Los Conquistadores. To complete the journey, you need buckets of adrenaline and an iron constitution. One contestant said that it kills brain cells. Time Magazine ranked it as one of the world’s top 10 endurance events. Those conquistadors must have been tough.

Crocodile Trophy

La Ruta Conquistadores isn’t for everyone, but imagine the emotions you go through during the Crocodile Trophy. As the name implies, the entire race is conducted along the backs of Northern Territory saltwater crocodiles laid end to end.

Actually, not really, but the mountain bike race touted as “the world’s hardest, longest, hottest and most adventurous” is only fractionally less tricky than that.

The Crocodile Trophy race spans 1,200km of Australia’s humming tropical north. The race takes a sinuous route along bone-jarring corrugated track from Cairns to Cooktown. Bicycles Network Australia describes it as, “definitely not an easy ride – there will be ups and downs, sharp turns and outback roads barely visited by car.”

Like the Race Across America, the Crocodile Trophy is said to be tougher than the Tour de France. Challenges include a near total lack of shade and bush fires that you must slice straight through. If you last it out, the epic journey takes 10 muscle-melting days. Don’t miss the top-notch website [http://crocodile-trophy.com] that nails the ride’s rollicking, gutsy character and features two fetching snapping crocs.

Cape Epic

What is it with ultra-hard bike races? They all seem to have cool names – none more so than Africa’s Cape Epic. The race, which lives up to its name, has been ranked “hors categorie.” That means “beyond categorization,” an incredibly tough climb. Hence the attention of some of the world’s top mountain bikers.

The yearly race happens around the last week of March. It lasts over 8 days, covering some 800 kilometers of the Western Cape.

En route you get to see some of South Africa’s most magnificent passes. The website raves about “majestic mountains, deep ravines, indigenous forests, spectacular coastlines and flourishing vineyards.” Against that, you have to tackle “dusty and demanding gravel paths,” and “strenuous rocky uphills,” among other hurdles. Beauty meets extreme difficulty here and, yearly, some 1000 adventure athletes take the challenge.

Route designer Leon Evans, nicknamed Dr Evil, is quoted saying that the race hurts like hell for all its 800 kilometers. Intrepid competitors ride in pairs.